Location: Jean Mayer Human Nutrition Research Center On Aging
2017 Annual Report
Objectives
LAB NAME: Nutritional Immunology
1: Determine the impact and underlying mechanisms of obesity during pregnancy on newborn's life-long immune and inflammatory responses and resistance to infectious diseases in appropriate animal models.
1A. To investigate the impact of maternal obesity on immune function and influenza infection in young offspring.
1B. To determine the role of inflammatory, oxidative stress, and selected epigenetic markers that are critical for immune response to influenza and the higher susceptibility of obese mothers’ offspring to influenza infection.
1C. To determine the impact of maternal obesity on immune function and resistance to infection through the life cycle.
2: Determine the effect and mechanisms of food components such as fruits and vegetables or whole grains influence on, and their interaction with, age on immune and inflammatory responses and related diseases in both animal models and human studies.
2A: To determine the impact of increased consumption of F&V on prevention of key age-related biologic dysfunctions and pathologies in a suitable animal model.
2B: To determine the effect of consumption of an isocaloric diet rich in whole grains (WG)[compared to refined grains (RG)] on gut microbiota, and immune and inflammatory responses.
LAB NAME: Vascular Biology
1: Determine the effectiveness and underlying mechanisms of fruits/vegetables and Mediterranean style diets or their specific bioactive components in the prevention of atherosclerosis and survival using animal models of humans.
1A: Determine the effectiveness and underlying mechanisms of increased consumption F&V diets on prevention of atherosclerosis and survival using appropriate animal model of human atherosclerosis.
1B: Determine the effectiveness of natural bioactive polyphenols of foods and spices and their underlying mechanisms on prevention of atherosclerosis using appropriate animal models of human atherosclerosis.
2: Determine the efficacy of fruits/vegetables, avenanthramides from oats, and selected other bioactive compounds on alteration of microbiome and anti-microbial peptides, suppression of chronic inflammation of the GI tract, prevention of colon cancer and atherosclerosis in appropriate animal models. Under this objective, we will pursue the following sub-objectives:
2A: Determine the efficacy of bioactive phosphorylated tocopherols ('Tp) versus tocopherols on age-dependent decline of angiogenesis and suppression of atherosclerosis in vivo and ex-vivo.
2B: To determine the molecular signaling mechanisms by which 'TP induces angiogenesis.
3: Determine the effect of eight weeks consumption of an isocaloric diet enriched with whole grains (compared to refined grains) on gut microbiota, inflammatory and other risk predictors of atherosclerosis.
Approach
NUTRITIONAL IMMUNOLOGY: Aging is associated with dysregulation of immune and inflammatory responses, which contribute to several age-related diseases. Nutritional status including that during early life has been linked to health status of older adults, & nutritional interventions during different life stages including those during pregnancy are reported to have long-lasting effects on the health status of newborns. Long-term goal is to determine the underlying mechanisms of age-related immune & inflammatory dysregulation in order to develop nutritional interventions, which will prevent/reduce these alterations. [1] will determine the impact & underlying mechanisms of obesity during pregnancy on newborn's life-long immune & inflammatory responses & resistance to infectious diseases. To achieve this, we will use a diet-induced obesity mouse model and determine: 1) effect of maternal obesity on immune function and influenza infection in young offspring, 2) role of inflammatory, oxidative stress, and selected epigenetic markers in altered immune function and susceptibility to infection in offspring born to obese mothers, and 3) impact of maternal obesity on immune function and resistance to infection through the life cycle. [2] will determine the effect and mechanisms of food components such as fruits and vegetables or whole grains influence on, and their interaction with, age on immune and inflammatory responses and related diseases in both animal models and human studies. [2A], we will use a mouse model to determine whether the dietary supplementation with a variety of fruits and vegetables would impact health- and life-span through modulating oxidative stress, inflammation and the regulatory lipid, ceramide. [2B], we will conduct a dietary intervention trial in healthy middle-aged human participants to determine the effect of consumption of an isocaloric diet rich in whole grains compared to refined grains on gut microbiota, and immune and inflammatory responses. These studies will help develop effective strategies to improve health- and life-span of the aged through optimization of immune and inflammatory responses.
VASCULAR BIOLOGY: Determine survival rates, prevention of atherosclerosis, and underlying mechanism(s) in LDLr-/- young to old mice using freeze-dried fruits, vegetables and cereal grains in a high fat diet. Further, we will use C57/BL and LDLr-/- mice to determine the causal relationship & underlying mechanism(s) of specific bioactive food components (such as curcumin, resveratrol, avenanthramides, and their combinations) on inhibition of dyslipidemia, fatty liver, inflammation, metabolic disorders, & atherosclerosis resulting from consuming a diet high in fat and/or sweeteners like sucrose & high fructose corn syrup. We plan to establish the causal relationship of increased consumption of whole grains versus refined grains and their capacity to improve oxidative & antioxidant status as well as surrogate markers of cardiovascular disease. We will investigate potential molecular mechanisms by which alpha-Tocopheryl phosphate (alpha-TP), a natural derivative of alpha-T, induces angiogenesis in vitro & in an in vivo animal model.
Progress Report
NUTRITIONAL IMMUNOLOGY LAB: While studies have linked maternal obesity (MO) to some immune disorders in offspring, it is impact on offspring resistance to infection is not known. Thus, we fed outbred female CD-1 mice (1-mo) a high fat (HF, 45%) diet or a low fat (LF, 10%) diet to induce obesity. Mice fed the HF diet had considerable variation in weight gain, which allowed us to further divide them into 2 groups: obesity-prone (high fat obese, HF-O) and obesity-resistant (high fat lean, HF-L). This enabled us to separate the impact of obesity from that of a high fat diet during pregnancy. Dams in all 3 groups (LF, HF-O, HF-L) were mated with 3-mo old male CD1 mice fed a standard chow diet and continued their respective diet during pregnancy and lactation. The offspring born to LF, HF-L, and HF-O dams were fed standard chow and monitored for their body weight for 10-mo. Effect of MO on offspring weight (WT) gain was gender-dependent: while male offspring in all groups had similar WT gain and percent fat, female offspring born to HF-O dams had less WT gain and percent fat than those born to LF dams. At 10-mo of age, offspring were infected with the influenza virus and monitored for 8 days. While all groups had post-infection WT loss, offspring in HF-L group had the most WT loss and more severe lung pathology than those in HF-O group. In addition, female offspring born to HF-O dams had higher T cell activity than those born to LF dams. These results were unexpected, not predicted from our hypothesis, and suggest that we needed to postpone the originally planned life-time longitudinal study in order to investigate the mechanisms underlying these observations, particularly, the gender-related difference. We are conducting a gene profiling study to identify the differences in genes and pathways that may guide us in focusing our mechanistic studies and future longitudinal studies.
Epidemiologic studies suggest that consumption of fruits and vegetables (F&V) is associated with reduced risk of diseases and may contribute to longevity. However, the causal relationship has not been established. The interventions using individual components of F&V have thus far shown inconsistent results. This is not surprising as foods and nutrients are consumed in combination, and interaction/synergy is likely to exist. Life-long interventional studies are needed to address this gap. Thus, we determined the impact of increased consumption of F&V with a normal fat or a high fat diet on key age-related biologic dysfunctions in animal models. The study has a combined longitudinal (following the same animals for life time) and cross-sectional (sampling every 6 mo) design; the outcome measurements include median life span, body weight and composition, oxidative stress, inflammation, immune response, and resistance to influenza infection. Before starting the longitudinal study, we conducted a pilot to determine the optimal F&V level to be used in the longitudinal study. Mice are fed a regular or high fat basal diet containing 0, 5, 10, or 15% F&V (w/w). After 4 mo, animals will be euthanized and samples collected for different measurement. Results show that mice fed a high fat diet with 15% F&V had significantly lower weight gain compared to mice fed a high fat diet and 0% F&V, even though their calorie intake is not significantly different than the control mice.
Although commensal bacteria are crucial in maintaining immune homeostasis of the intestine, little is known about lung commensal bacteria’s role in shaping the immune response and aging. To address this gap, we conducted a study to systematically look at the pulmonary microbiome of healthy older individuals through analysis of high-throughput 16SrDNA sequence data from broncho-alveolar lavage. We plan to enroll 15 healthy young (21-30 y) and 15 older (>/=65 y ) participants. Six young and 8 older participants have been enrolled; blood samples for immunological outcome measures have been analyzed. We evaluated TLR function in human alveolar macrophages (AM) from 6 young (age 21-30 y) and 8 older (=65 y) individuals. Using multicolor flow cytometry and intracellular cytokine staining of AMs, we found substantial decreases in older compared to younger individuals in TNF-alpha, IL-6, IL-12 (p40) and IFN-alpha production in response to TLR1/2, TLR2/6, TLR3, TLR5, TLR7, TLR8, and TLR9 stimulation. Pulmonary microbiome data are currently being analyzed.
VASCULAR BIOLOGY LAB: Consumption of fruits and vegetables (F&V) is suggested to reduce risk of cardiovascular disease (CVD). We have conducted studies to determine the effect of either specific foods like mushrooms or mixed F&V in preventing atherosclerosis. The benefit of F&V is most often viewed as an “association in observational studies;” therefore, there is limited data to demonstrate a “causal relationship.” It is also believed that diets high in F&V increase fiber intake, balance of antioxidants/oxidative stress, and they improve lipid profile and reduce inflammation in atherosclerosis. In a pilot study, to prove a health-promoting effect of F&V on prevention of CVD, we prepared a freeze-dried powder of 12 fruits and vegetables commonly consumed in the U.S. We added 10% of this preparation into a high fat diet of LDLr-/-mice for 16 wks. Results thus far show that mice consuming the high fat diet with F&V have gained less body weight and body fat. Mice will be sacrificed within the next few weeks to obtain measurements of aortic lesions and related biochemical indicators.
In collaboration with the Energy Metabolism Lab, we have begun a study investigating the body fat and weight reducing effect of enzymatically-modified isoquercetrin (EMIQ), a natural bioactive polyphenol with potential health benefits to prevent CVD. EMIQ is a mixture of quercetin monoglucoside and its a-oligoglucosides. (Quercitrin is widely found in plant foods like onions, broccoli and apples.) In animal models and human trials in Japan, supplemental intake of EMIQ reduced body fat and weight. However, it is uncertain if this effect will also be observed in people consuming Western-style diets. Thus, in a double-blind, placebo-controlled study we will test EMIQ in body fat and weight reduction in people consuming a Western-style diet. A total of 50 overweight and obese subjects will be assigned into two groups: 25 subjects to a placebo control group, 25 subjects to EMIQ group (300 mg/d for 3 months). Currently, 25 subjects are enrolled, and 25 more will be recruited. Several parameters including body composition, resting metabolic rate and skin fold are being measured. At present, this study is on course to be completed on time.
Mushrooms have recently become an important choice in a healthy diet. Mushrooms are low in sodium and are good sources of fiber, bioactive compounds, selenium, potassium and vitamin D, all of which may contribute to a healthy heart through their anti-inflammatory and anti-atherogenic activities. A few studies have shown suppressive effects of edible mushrooms on atherosclerosis. Therefore, we are studying the effect of two commonly consumed edible mushrooms, portobello (PBM) and shiitake mushroom (SHM), on the prevention of atherosclerosis and related inflammation in LdLr-/- mice by feeding them diets that include a freeze-dried powder of these two mushrooms. Adding 10% mushroom powder to the mice’s diets reduced their body fat and weight gain over 16 wks. We found that SHM was more effective at reducing weight gain in mice fed a high fat (HF) diet. Analysis of aortic lesions revealed that only the mice fed HF-SHM had significantly fewer aortic lesions compared to those fed the high fat control diet. Our results suggest that high levels of bioactive compounds such as ergothioneine may suppress dietary fat-induced atherosclerosis. We have shown that oats’ avenanthramides (Avns) can inhibit inflammatory cytokines and adhesion of monocytes to endothelial cells in culture; thus, they may prevent atherogenesis. Using an Ldlr-/- mouse, we found that feeding mice a high fat diet containing oats with high levels of Avns inhibited atherogenesis. The high Avns oats were prepared through false-malting by our collaborator from Agriculture Canada, and the analysis of Avns in the blood was done by ARS Cereal Crops Research Unit, Madison, Wisconsin.
Vitamin E, specifically alpha tocopherol (aT), is a fat-soluble vitamin with strong antioxidant activities. Supplemental intake of aT is associated with preventing or treating several diseases. Alpha-Tocopheryl phosphate (aTP) is a natural analogue of aT occurring in low concentration in foods, animal and human tissues. There is evidence that a transporter is mechanistically involved in the uptake of aTP by tissues. In a cell culture study, we discovered that internalization of CD36 in THP monocytes is triggered by aT and more strongly by aTP. Evidence suggests that aTP may play important role in regulating vascular endothelial growth factor (VEGF) expression. In several studies, vitamin E has been observed to influence angiogenesis and vasculogenesis. We recently showed that aTP may act as an active lipid mediator increasing VEGF expression. We have found that the induction of the VEGF promotor activity by aTP occurs via CD36/PI3K. These new findings suggest that aTP activates the PI3K/Akt signaling pathway, leading to VEGF expression in monocytes after binding to and/or transport by CD36, a receptor known to modulate angiogenesis. These findings may have several potential health implications such as aTP’s effect on vasculogenesis, angiogenesis in wound healing, and tumor growth and cancer development.
Accomplishments
1. IMMUNOLOGY LAB: Whole grains improve gut health and immune function in healthy adults. A health benefit of whole grain (WG) consumption may be associated with lower inflammation, a key factor in the development of chronic diseases like cardiovascular diseases, cancer, and diabetes, but this notion is largely based on epidemiological studies and only a limited number of interventional studies. In a clinical trial, ARS-funded researchers in Boston, Massachusetts, compared WG and refined grain (RG) diets for their effect on several important markers of gut health and immune function. They found that the WG diet was well-tolerated by the participants and that compared to RG group, WG group had significant increases in stool weight and frequency, beneficial dietary fiber products, and some beneficial gut-residing bacteria known to have an anti-inflammatory effect. In addition, a modest beneficial change in immune function was observed. These results show, for the first time, that increasing consumption of whole grains without weight loss improves gut health and certain immune functions, and these observations have added new evidence supporting the current USDA dietary guidelines that recommend increased whole grain intake.
2. VASCULAR BIOLOGY LAB: The risk of cardiovascular disease (CVD) can be reduced by consuming oats. Inflammation of the blood vessels and high levels of cholesterol can contribute to the development of cardiovascular diseases, i.e. conditions that impact the heart and blood vessel system. Through good nutritional choices, we can help reduce this inflammation and the amount of cholesterol in our bloodstream, thereby lowering the risk of developing these diseases. ARS-funded researchers in Boston, Massachusetts, demonstrated that eating oats containing high levels of avenanthramides (AVNs), a substance found naturally in all oats, reduces inflammation in blood vessels. The researchers have specifically learned that AVNs are most beneficial for lowering inflammation and cholesterol when the oats have a high level of these AVNs. Since oats are an important U.S. agricultural product, these scientific results can be used to guide oat breeding in order to produce a crop with high levels of AVNs, thereby enhancing the health benefits of this food.
Review Publications
Vanegas, S.M., Meydani, M., Barnett, J.B., Goldin, B., Kane, A., Rasmussen, H., Brown, C., Vangay, P., Knights, D., Jonnalagadda, S., Koecher, K., Karl, J., Thomas, M.J., Dolnikowski, G.G., Li, L., Saltzman, E., Wu, D., Meydani, S.N. 2017. Substituting whole grains for refined grains in a 6-wk randomized trial has a modest effect on gut microbiota and immune and inflammatory markers of healthy adults. American Journal of Clinical Nutrition. 105:635-650. doi: 10.3945/ajcn.116.146928.
Zingg, J-M., Hasan, S.T., Nakagawa, K., Canepa, E., Ricciarelli, R., Villacorta, L., Azzi, A., Meydani, M. 2016. Modulation of cAMP levels by high fat diet and curcumin and regulatory effects on CD36/FAT scavenger receptor/fatty acids transporter gene expression. Biofactors. doi: 10.1002/biof.1307.
Bou Ghanem, E.N., Lee, J.N., Joma, B.H., Meydani, S.N., Leong, J.M., Panda, A. 2017. The alpha-tocopherol form of vitamin E boosts elastase activity of human PMNs and their ability to kill Streptococcus pneumoniae. Frontiers in Cellular and Infection Microbiology. doi: 10.3389/fcimb.2017.00161.
Yuan, C., Spiegelman, D., Rimm, E.B., Rosner, B.A., Stampfer, M.J., Barnett, J.B., Chavarro, J.E., Subar, A.F., Sampson, L.K., Willett, W.C. 2017. Validation of a dietary questionnaire assessed with multiple weighed dietary records or 24-hour recalls. American Journal of Epidemiology. doi: 1093/aje/kww104.
Mazidi, M., Karimi, E., Meydani, M., Ghayour-Mobarhan, M., Ferns, G.A. 2016. Potential effects of curcumin on peroxisome proliferator-activated receptor-gamma in vitro and in vivo. Review Article. 6(1):112-117.
Pae, M., Wu, D. 2017. Nutritional modulation of age-related changes in the immune system and risk of infection. Nutrition Research Reviews. 41:14-35. doi: 10.1016/j.nutres.2017.02.001.
Karl, J.P., Meydani, M., Barnett, J.B., Vanegas, S.M., Goldin, B., Rasmussen, H., Saltzman, E., Chen, C., Das, S., Jonnalagadda, S.S., Meydani, S.N., Roberts, S.B. 2017. Substituting whole grains for refined grains in a 6-week randomized trial favorably affects energy balance parameters in healthy men and post-menopausal women. American Journal of Clinical Nutrition. 105:589-599. doi: 10.3945/ajcn.116.139683.
